title: Characterization of a glycoside hydrolase family 31 α-glucosidase involved in starch utilization in Podospora anserina.
abstract: For Podospora anserina, several studies of cellulolytic enzymes have been established, but characteristics of amylolytic enzymes are not well understood. When P. anserina grew in starch as carbon source, it accumulated glucose, nigerose, and maltose in the culture supernatant. At the same time, the fungus secreted α-glucosidase (PAG). PAG was purified from the culture supernatant, and was found to convert soluble starch to nigerose and maltose. The recombinant enzyme with C-terminal His-tag (rPAG) was produced with Pichia pastoris. Most rPAG produced under standard conditions lost its affinity for nickel-chelating resin, but the affinity was improved by the use of a buffered medium (pH 8.0) supplemented with casamino acid and a reduction of the cultivation time. rPAG suffered limited proteolysis at the same site as the original PAG. A site-directed mutagenesis study indicated that proteolysis had no effect on enzyme characteristics. A kinetic study indicated that the PAG possessed significant transglycosylation activity.
authors.affiliation: Research Faculty of Agriculture, Hokkaido University.
authors.forename: Kyung-Mo
authors.initials: KM
authors.lastname: Song
authors.forename: Masayuki
authors.initials: M
authors.lastname: Okuyama
authors.forename: Kazuyuki
authors.initials: K
authors.lastname: Kobayashi
authors.forename: Haruhide
authors.initials: H
authors.lastname: Mori
authors.forename: Atsuo
authors.initials: A
authors.lastname: Kimura
mesh_terms: D003001:Cloning, Molecular; D046508:Culture Techniques; D018076:DNA, Complementary / Q000235:genetics; D006031:Glycosylation; D007700:Kinetics; D016297:Mutagenesis, Site-Directed; D010455:Peptides / Q000378:metabolism; D048468:Podospora / Q000201:enzymology* / Q000254:growth & development; D011994:Recombinant Proteins / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D012995:Solubility; D013213:Starch / Q000737:chemistry / Q000378:metabolism*; D013379:Substrate Specificity; D000520:alpha-Glucosidases / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*
chemical_list: D018076:DNA, Complementary; D010455:Peptides; D011994:Recombinant Proteins; D013213:Starch; D000520:alpha-Glucosidases